Child performers in both the circus and on the stage are under enormous pressure to travel and stay up late nights to perform for audiences. Acrobatics may be too hard on some children as they may get hurt either in front of an audience or in rehearsals. Child performers will likely never be banned, but at least let children be children and give them a break every once in a while.
Some physical performances are just not something young children should do. Should young children be allowed to play tackle football, or box, or things like that? Of course not. Young children are simply not developed to the point that they can do things that teenagers and adults can do and this is simply a fact.